The invention relates to a slit lamp device and a lens supporting unit as an attachment for the device.
A slit lamp microscope is known, for example from the company Haag Streit under the name xe2x80x9cOriginal slit lamp 900 BMxe2x80x9d and is described with its essential features in DE-A 1 133 911. The known slit lamp device had a viewing unit for stereoscopic examination of the eye and an illumination unit for the eye which is to be examined. The cross section of a illumination spot on or in the eye can be adjusted by a diaphragm which is adjustable in width and height. The illumination unit was located on a vertically running branch of a holding unit. The eye to be examined could be positioned in a roughly horizontally running plane on one side of the holding unit. The viewing unit was located roughly in the plane on the side of the holding unit opposite it. The holding unit had three columns. The illumination optics rested on the two outer columns. On the third middle column which was made as a stub column there was a deflection mirror which guided the beam of the illumination unit to the eye. In the intermediate spaces between one outer column at a time and the stub column the beam paths were guided to the viewing unit.
In U.S. Pat. No. 5,216,456 a three-column slit lamp device is described, the middle column bearing the deflection mirror for illuminating the eye. All three columns are joined via a connecting plate on which then an illumination unit is placed.
In U.S. Pat. No. 4,331,392 the illumination unit is located in the lower part of the slit lamp device and thus necessarily has a construction which is completely different from the invention; in it the illumination unit is located at the top. The arrangement of an illumination unit in the upper part of the slit lamp device compared to the arrangement of U.S. Pat. No. 4,331,392 allows simple replacement of the illumination source. The slit lamp device of U.S. Pat. No. 4,331,392 is foreign to that of the invention and thus not further examined below.
In EP-A 0 091 334 a slit lamp device is described with which the eye could be examined and a laser beam was guided for eye treatment. The slit lamp device of EP-A 0 091 334 was built analogously to that of DE-A 1 133 911, an additional column stub being present for guidance of the laser beam. The analogous structure can be seen especially in FIG. 2 which shows a vertical lengthwise section through the device. FIG. 2 shows cutaway the middle column which bears the deflection mirror. Furthermore, the left side column is shown as seen from the visual field of the patient. The connecting plate for the two side columns on which the illumination unit (here labelled 20) sits is shown cutaway.
The object of the invention is to devise a slit lamp device which allows good patent-physician contact, ensures efficient examination and which can be economically produced in an aesthetically pleasing form with outstanding optical properties.
The invention is characterized by as little material as possible between the observing and examining physician and the patient in order to ensure efficient examination and good patient-physician contact. A structure which avoids material between the physician and patient is achieved by means of a vertically running branch of a holding unit for an illumination unit made as one column with a narrow column cross section. The narrow column area is preferably made at eye height. Efficient examination is furthermore supported by a video recording. The compact configuration achieved likewise enables economical manufacture. The features of the invention also increase the examination efficiency since the viewing, observing or examining individual need no longer turn his gaze from the viewing unit to look for the controls. The most important controls can be operated with only one hand.
If a Greenough microscope is used as an observation unit preferably in conjunction with the slender holding column as a holding unit, a further reduction in the size of the device results. The video viewing arrangement described below with a Greenough microscope can also be used on other slit lamp devices with the corresponding adaptation. Also the size of the device can be reduced; but its mass does not decrease as much as when using the single-column holding unit.
One partial beam which is guided to a recording element of a recording unit is masked out into one of the two beam paths of the Greenough microscope for display and evaluation purposes. If the decoupling of the partial beam as was the case in conventional slit lamp devices, having a different microscope than a Greenough microscope, were to take place, much larger dimensions would result.
The structure described below furthermore easily allows integration of optical filters which enable better observation results.
In one preferred version, a lens supporting unit can simply be slipped on as an accessory. With this accessory part, studies can be done on the vitreous body and on the ocular fundus. These examinations have been done in the past with a so-called xe2x80x9cmovable Hruby adapter glassxe2x80x9d. This means had a rod on which one examination lens was arranged with a capacity to swivel. The rod had a vertically running guide rod which was guided in the direction of the patient in one slot on the slit lamp device. This guide rod led through an attachment plate which was attached to the chin holder for the patient""s head. Directly underneath the lens there was a small lever as the handle for moving the lens. The examinations performed with the known xe2x80x9cadapter glassxe2x80x9d were often not reproducible since when the lever was released generally the lens moved. Photographs for documentation were thus hardly possible.
Embodiments and other advantages of the invention are described below.